Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 9-10

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 79-86

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 92-110

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 111

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 121-122

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 126-148

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 149

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 151-159

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 160

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 162

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 163-175

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 176

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 416-422

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 429

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 435-439

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 443

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 448-453

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 460-463

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 472-485

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1881, in volume 33, pages 502-505